The invention relates to a device for measuring distances according to the preamble of claim 1, and a distance-measuring instrument for this device according to the preamble of claim 5 and a stop element for this device according to the preamble of claim 7.
Devices for measuring distances, comprising a combination of a distance-measuring instrument, preferably a laser distance-measuring instrument, and a holder for positioning and for fixing the distance-measuring instrument, are generally known and are used in many areas. These holders effect exact positioning of the distance-measuring instrument relative to a reference point, so that various measurements can be transferred to a common reference system. Moreover, they ensure stable retention during the measuring process.
A point which serves as a reference point for measured distances, is to be defined here as the reference point, i.e. all values actually measured by the distance-measuring instrument must be converted so that they correspond to the distances in the reference system. As a rule, in the case of an installation at a point, for example at a wall in a building, it is therefore also necessary to take into account the housing parts of the distance-measuring instrument and any installation parts which serve for positioning the distance-measuring instrument.
The holders of the prior art are generally in the form of tripods and the distance-measuring instrument is fastened by means of a thread and threaded bush, mobility about two axes (horizontal and vertical) generally being ensured. This type of holder is used in particular in the area of geodetic surveys.
In other areas, too, it is necessary to install the distance-measuring instrument on an object or a reference point in a defined manner in order to permit an exact measurement of the distance to another object. In particular, use in the construction sector requires a high accuracy of measurement in the case of a very wide range of surfaces and reference points. Examples of such measurements are building spacings, ceiling heights and internal diameters of openings. Owing to the building structures, measurements frequently also have to be carried out from corners, resulting in particular requirements with respect to size and handling properties of the distance-measuring instrument. The frequently highly structured ground gives rise to problems with the exact installation and hence the positioning of the distance-measuring instrument. For example, holes, edges, rounded areas or wire meshes make it more difficult to position the device exactly. It may also be of interest to be able to survey liquid levels, for example the water level in a space; however, the surveying of liquid surfaces by means of the distance-measuring instruments of the prior art is not possible without complicated aids.
The main requirement with regard to the holder is thus associated with the positioning of the distance-measuring instrument relative to a point or in a plane, by means of which the various measurements can be transferred to a standard reference system. Moreover, the achievable accuracy during the measuring process can be increased by mechanically firm fixing.
The main difficulties here are the defined installation at the reference point to be surveyed and the mechanically sufficiently stable fixing of the device during the measurement on the object. A defined installation can be realized only with difficulty particularly in the case of poorly accessible points, such as, for example, in angled surfaces, or in the case of objects having a disadvantageous surface, such as, for example, a very soft or curved surface. In addition to the accessibility of the measuring point, which can be ensured, for example, by a simple, hinged spike, there is a requirement for secure fixing of the measuring device during the measurement. Aids necessary for this purpose frequently result in a deviation from the ideal installation at the measuring point. The distance-measuring instrument must be positioned with the aid of a holder or a supporting construction. If the distance-measuring instrument cannot be installed therewith directly at the point actually to be surveyed, at least the distance from the actual measuring location to this point must be known.
If a measuring stop is used for the installation, as can also be assumed to be known from other areas of measurement technology, this additional distance of the measuring point, produced by the measuring stop, must be taken into account in the measurement.
The realization of such a measuring system is subject to various specifications. The requirements with regard to the measuring device are good handling properties, the necessary precision and a small size which makes it possible to reach and to survey all relevant areas.
The generally hand-held laser distance-measuring instruments used for this purpose are widely employed. A device of this type is described, for example, in EP 0 738 899 B1.
The exact positioning of the distance-measuring instrument on the object to be measured generally proves problematic. Thus, for example, the measurement of a distance between a smooth wall and pipe requires the installation of a distance-measuring instrument on a curved surface if the advantage of a wall as a flat reflecting surface is to be retained.
It is the technical object of the present invention to provide a device and its components comprising distance-measuring instrument and stop element, which ensure defined and sufficiently fixed installation of the distance-measuring instrument on surfaces of virtually any desired shape.